Backup Storage Calculator

Calculate total storage required for full and incremental backup retention schemes.

Backup Storage Calculator Live Calculation
Backup Storage Required (Estimate):
7.67 TB
In Gigabytes:7,666.67 GB
Total Raw Before Dedupe:11.50 TB
Full Backups:5 Fulls (25 Incs)
Backup Model Assumptions: Standard forward incremental model with weekly synthetic or active full backups (every 7 days) and daily incremental backups. Deduplication efficiency depends heavily on workload data types (pre-compressed video archives compress far less than database transaction logs). Note: Differential backups (which store cumulative daily changes since the last full backup) require a separate sizing model and are not calculated here.

What is the Backup Storage Calculator?

Essential for systems administrators planning backup appliances (Veeam, Synology, TrueNAS) and disaster recovery targets.

How to Use This Tool

Input primary data volume, daily change rate percentage, retention policy (number of full and daily backups), and compression ratio.

Formula & Calculation Logic

The mathematical formula used to calculate this conversion is:

Total Raw = (Full Backups × Source Size) + (Incremental Backups × Source Size × Daily Change %); Required Storage = Total Raw ÷ Deduplication Ratio

Step-by-Step Example Calculation

Here is a real-world calculation example demonstrating the mathematics:

Example: 2,000 GB (2 TB) source data, 30 days retention, 7-day full backup interval, 3% daily change rate, 1.5× deduplication/compression Full backups: 1 + floor((30 - 1) / 7) = 5 full backups (5 × 2,000 GB = 10,000 GB) Incremental backups: 30 - 5 = 25 daily incrementals (25 × 60 GB = 1,500 GB) Total Raw Storage: 10,000 GB + 1,500 GB = 11,500 GB (11.5 TB) Effective Storage Needed: 11,500 GB ÷ 1.5 = ~7,666.67 GB (~7.67 TB) (At 0% daily change rate, raw storage is 10,000 GB and effective storage is ~6,666.67 GB / 6.67 TB)

Frequently Asked Questions

Keep 3 copies of your data on 2 different media types, with at least 1 copy stored off-site or in the cloud.

Most enterprise file servers experience a 1% to 5% daily change rate, while active transactional databases can see 5% to 15%.